Oily iodine compounds, currently employed in myelography and lymphography, are far from ideal as diagnostic contrast agents. The high viscosity of iodized oils renders the process of administration difficult and time-consuming and inflammatory responses and hypersensitivity to iodine compounds have been observed. Our laboratory has developed a new contrast agent - Perfluoroctylbromide (C8F17Br). This radiopaque perfluorocarbon is extremely stable physically and chemically and non-toxic. The efficacy and safety of perfluoroctylbromide in bronchography, alveolography and gastroenterography have been established and an Investigational New Drug Exemption was filed with the FDA on January 9, 1973. Preliminary experiments in myelography and lymphography show that C8F17Br is well tolerated. Cerebrospinal fluid analyses indicate minimal irritation with C8F17Br. Due to its low surface tension and low viscosity, administration is easier with both intrathecal injection and direct lymphatic infusion. Perfluoroctylbromide can be made miscible with the body fluid by emulsifying the fluid in normal saline. The C8F17Br emulsion has slightly lower radiopacity but greater rate of absorption from the connective tissues into the lymphatic system. Due to its non-irritability and its lymphotropic property C8F18Br may prove to be an ideal contrast agent for indirect lymphography. The objective of the research is to develop preparations and techniques with C8F17Br in myelography and lymphography. The biologic disposition of C8F17Br will be investigated following intrathecal and lymphatic administration. Our goal is the clinical application of perfluoroctylbromide in evaluation of the structure and function of the CNS and the lymphatic system.